Cast part for an internal combustion engine

ABSTRACT

The invention relates to a cast part for an internal combustion engine, said part being a cylinder crankcase, which has at least one guide duct that leads a fluid medium to a required location. Said guide duct is provided in the form of a tube and is embedded inside the part when the latter is cast. The aim of the invention is to reduce the complexity of production and the costs of the cylinder crankcase. To this end, the fluid medium is provided in the form of oil and the at least one guide duct is provided in the form of an oil supply leading to a crankshaft bearing and/or to a camshaft bearing that are to be lubricated or to other required location.

CROSS REFERENCE TO RELATED APPLICATIONS

Applicant claims priority under 35 U.S.C. § 119 of German ApplicationNos. 102 55 284.3 and 103 04 971.1 filed Nov. 26, 2002 and Feb. 6, 2003,respectively. Applicant also claims priority under 35 U.S.C. § 365 ofPCT/DE2003/003901 filed Nov. 25, 2003. The international applicationunder PCT article 21(2) was not published in English.

The present invention relates to a cast part for an internal combustionengine, the part being a cylinder crankcase, which has at least oneguide duct that leads a fluid medium to a required location, the ductbeing implemented in the form of a tube and being embedded inside thepart when the latter is cast.

Internal combustion engines are an essential component of vehicles (suchas passenger automobiles and utility vehicles, ships, etc.) in the formof internal combustion engines and are also used as stationary engines.In this case, internal combustion engines contain numerous castcomponents which have at least one guide duct (also referred to as asupply line) that leads a fluid medium (e.g., oil, water, gas, or otherliquid and/or gaseous media) to a required location in the engine and/orin adjoining regions. Some of the guide ducts may also be used forcooling a part themselves. Required locations are the points at whichthe particular medium is necessary, e.g., bearings to be lubricated,regions to be cooled, etc.

A guide duct and/or multiple guide ducts particularly occur in acylinder crankcase and/or attachments neighboring thereto. Guide ductsare introduced in a known way through mechanical machining on machinetools and/or transfer lines, i.e., drilled. For this purpose, centralmain guide ducts and secondary guide ducts which form branches to theindividual required locations are drilled into the part in multiplecomplex work steps, which are to be performed with high precision.Subsequently, numerous unnecessary accesses must be closed permanentlyand securely. Very long, linear guide ducts, such as those of the mainoil duct in a cylinder crankcase, are currently even cast individuallyby casting around a tube or through relief by an appropriate castingcore.

Embedding cooling ducts, which are preformed as tubes, having a smalldiameter in a cast cylinder block and/or cylinder head of an internalcombustion engine during manufacturing is known from DE 199 61 092 A1.These lead around components such as spark plugs or fuel injectionnozzles and form a cooling system for the liquid cooling of the internalcombustion engine. DE 33 00 924 C2 teaches, for water cooling of websbetween cylinders of a cylinder block of a water-cooled internalcombustion engine, which are cast closely and directly together,embedding tubes in the cast material which forms the webs, these tubesproducing a connection between the lateral coolant water mantels of thecylinder block. Intensive cooling of the highly stressed web regionsthus results.

The present invention is based on the object of reducing themanufacturing effort and costs in a part—specifically a cylindercrankcase—of the above-mentioned type and suggesting a method formanufacturing a part according to the present invention.

This object is achieved according to the present invention for a castpart of the above-mentioned type by the characterizing features of Claim1, Claim 14, Claim 17, or Claim 19.

According to the present invention, the cast part is a cylindercrankcase. A cylinder crankcase has numerous guide ducts, particularlyfor oil and water, so that by embedding a guide duct or multiple guideducts, which is/are each implemented as a tube, a significant savings inmanufacturing effort is achieved. In the case of a single guide ductembedded as a tube, this is not the main oil duct, since this is part ofthe related art. The object of the present invention is rather,(possibly in addition to embedding the main oil duct as a tube) to embedanother guide duct or multiple other guide ducts for oil and/or othermedia to required locations as tube(s). For example, the oil supplylines to crankshaft and/or camshaft bearings, the supply line for pistoncooling, the pressurized oil line to the cylinder head or oil returnlines are to be cited as essential guide ducts to required locations ina cylinder crankcase which may advantageously be implemented accordingto the present invention in the form of embedded tubes.

Furthermore, at least one guide duct which forms a fuel line may beembedded as a tube in the cylinder crankcase.

In the cylinder crankcase according to the present invention accordingto Claim 1, the at least one guide duct embedded in the cylindercrankcase as a tube is used for the purpose of supplying a bearinglocated in the cylinder crankcase with oil for lubrication, i.e., itforms an oil supply line. The guide duct expediently runs in the regionof a separation wall of the cylinder crankcase for this purpose.

In the cylinder crankcase according to the present invention accordingto Claim 14, at least one guide duct is embedded as a tube, which formsan oil supply line for supplying the piston cooling and/or lubricationof the cylinder wall. To save labor effort, it is advantageous ifmultiple pistons and/or cylinders may be supplied from a shared oilsupply line. For this purpose, the oil supply line may expediently beimplemented and positioned in such a way that it runs in thelongitudinal extension of the cylinder crankcase and multiple spraynozzles branch from it, which each spray oil directed into a cylinderchamber below a piston floor, through which the piston floor is cooledand, in addition, the affected cylinder wall is lubricated. Of course,multiple oil supply lines to one cylinder or to multiple cylinders,possibly having other courses, may also be embedded.

In the cylinder crankcase according to the present invention accordingto Claim 17, at least one guide duct is embedded as a tube which formsan oil supply line for the oil supply of the cylinder head and/or thecylinder heads. The oil supply line may be fed with oil directly fromthe main oil duct or from a downstream region of the oil economy withinthe cylinder crankcase.

In the cylinder crankcase according to the present invention accordingto Claim 19, at least one guide duct is embedded as a tube which forms afuel line for supplying a fuel pump. The fuel line advantageously runsin the longitudinal extension of the cylinder crankcase in the region ofa crankcase external wall. In an advantageous refinement, multiple fuellines are embedded as tubes, e.g., at least one feed line and at leastone return line.

Embedding a pre-manufactured tube as a guide duct has the advantage overmechanical introduction through drilling that the guide duct does nothave to run linearly (as with drilling), but rather may be tailored tothe required contour course of the part having the particular desiredbends. In contrast to this, with linear drilling of a guide ductaccording to the related art, manufacturing paths which are not usefulfor supplying the required locations must automatically be employed.Furthermore, a hole has an access to the outside, which mustsubsequently be closed again, which may lead to sealing problems. Thedisadvantages and problems of this type do not occur with a guide ductembedded in the form of an appropriately pre-manufactured and/or shapedtube.

A further advantage of the present invention is that an embedded tubeguide duct and/or multiple embedded tube guide ducts provide a very highdegree of cleanliness on the internal duct wall and the cavity, incontrast to the related art, is free of residues as a result ofmechanical introduction of the duct and/or free of casting residues(e.g., core residues) as a result of embedding the duct in the componentas a cavity by inserting a core.

This aspect is especially important in a guide duct for bearinglubrication, since residues possibly remaining in the duct reach thebearing with the oil during engine operation and would result indestruction of the bearing.

In addition, it is possible, in contrast to a drilled guide duct, inwhich only circular cross sections may be implemented, to introduce theduct with nearly any desired cross-sectional shape and thus optimize thecourse and the supply. Furthermore, through suitable selection of thecross-sectional shape, the thickness of the part wall in which the guideduct is embedded may also be reduced, which results in a weightreduction of the part.

Of course, it is possible to provide one or more guide ducts embedded asa tube according to the present invention and one or more guide ductsintroduced in typical ways on the same part.

In an advantageous refinement of the present invention, the at least oneguide duct embedded as a tube is positioned in such a way that it runspartially or entirely exposed in some sections, i.e., it may run outsidethe part wall on its outside and/or inside. The guide duct may, incontrast, be locally enclosed with casting material of the part, like a“shell”, in order to ensure the permanent bond of duct and part. Theguide duct may (in relation to its longitudinal extension) runcompletely exposed or, however, be partially embedded in the part wall.The measure of the sectionally exposed course offers the advantage inrelation to the related art, in which the guide ducts that are drilledin or embedded using cores may only run in the wall of the part, thatthe wall thickness of the part may be significantly reduced and materialand weight may thus be saved.

According to an advantageous refinement of the present invention, the atleast one embedded guide duct has different cross-sectional shapes inits course. In this way, good adaptation to the particular constructionof the part is achieved. For example, narrow contoured regions may beovercome. The particular cross-sectional shapes to be implemented dependon the particular construction of the part. Different cross-sectionalshapes may be implemented on a tube before the embedding, e.g., throughhydroforming of the tube.

According to an advantageous embodiment of the present invention, thepart is cast from a metallic material or plastic. The at least oneembedded guide duct may also advantageously be manufactured from ametallic material or plastic. For example, steel, all cast ironmaterials, light metals, and nonferrous heavy metals come intoconsideration as metallic materials. The specific material which ispreferably to be used is also a function of, among other things, theparticular part to be cast.

Depending on the cast cylinder crankcase, it may be expedient to provideonly one single guide duct embedded as a tube in the part. The partadvantageously comprises multiple embedded guide ducts in order to savemanufacturing effort and costs. In an advantageous variation, the guideducts may each be introduced as a single connection tube for the mediumguiding. I.e., multiple individual appropriately shaped tubes are alsoembedded as connecting parts during casting. This offers a high degreeof freedom in regard to the course of the guide ducts. According to afurther alternative advantageous variation, the embedded guide ducts areimplemented by a branched tube system. For this purpose, multiple tubesare connected to one another to form a tube system (e.g., welded) beforethe casting and subsequently the tube composite is also embedded. Acombination of guide ducts in tube composite form and individualconnection parts on the same part is also possible and advantageous.

Of course, embedded tubes implemented and positioned according to thepresent invention may also be implemented as guide ducts in anattachment of a cylinder crankcase—particularly in a cylinder head, agear case, a chain case, an oil pan, or the like. In this case, guideducts in the cylinder crankcase and/or in the attachment(s) may besupplied by a shared supply loop or multiple supply loops.

The above-mentioned object is also achieved by a method formanufacturing a cast part for an internal combustion engine, the partbeing a cylinder crankcase, which has at least one guide duct thatguides a fluid medium to a required location, a tube having the desiredcourse being installed in a casting mold required for casting orintroduced into a casting core or incorporated into a lost model and/orinto its mold medium cavity filler to form the at least one guide ductand subsequently the part being cast using the particular casting methodto be employed.

According to the present invention, the tube may also be introduced intomultiple casting cores which may be assembled as individual cores into acore block.

According to this casting concept it is possible to manufacture a parthaving at least one embedded tube guide duct—preferably a cylindercrankcase (but other parts may also be advantageously implemented asattachments for the cylinder crankcase (e.g., cylinder head, gear case,chain case, oil pan, etc.). Depending on whether the at least one guideduct is to be completely embedded in the part wall or is to be;partially or completely exposed, the tube to be embedded is installed inthe casting mold (possibly using supports) and/or introduced into thecasting core (e.g., inserted into a sand core or also incorporatedduring the core manufacturing) or incorporated into a lost model and/ordirectly embedded in its mold medium cavity filler, or the tube ismounted on one tube end in the casting core. When introducing a tubeinto the casting core, specific regions are to be exposed again in orderto produce a solid cast connection to the part. After the casting usingthe particular casting method to be employed, the cast rough part isremoved from the mold, cores and/or loose form medium are removed, andthe typical finishing measures are performed.

A cast part according to the present invention may be manufactured usingdifferent casting methods. According to a first advantageous methodvariation, the part is cast in a casting method using a lost mold, e.g.,in a pure core mold method, a core mold in combination with green-sandmold method, a core mold in combination with cold resin mold method,etc. According to a second advantageous method variation, the part iscast in a casting method using a permanent mold, e.g., chill casting,die casting, injection molding, etc. In a third preferred variation, thepart is cast in the lost foam method. Advantages of the lost foamcasting method (a form of full mold casting) are, for example, the lackof core residues on the cast part, the high surface quality,high-quality contour sharpness, and great imaging precision andtherefore a relatively low finishing effort.

If the part is to have multiple embedded guide ducts, the tubesnecessary for this purpose may preferably be introduced as individualconnection tubes. It may also be advantageous to connect multiple tubesinto a corresponding tube system, to position the pre-manufactured tubesystem in the casting mold, core, etc., and subsequently to embed it.Furthermore, it may be advantageous in some variations to connectmultiple tubes into a partial tube system and to embed multiple partialtube systems in the part. Which variation is to be preferred is afunction of the particular concrete task.

Exemplary embodiments of cylinder crankcases according to the presentinvention are schematically illustrated in the drawing.

FIG. 1 shows a detail of a cross-section of a cylinder crankcaseaccording to the related art,

FIG. 2 shows a detail of a longitudinal section from FIG. 1 (relatedart),

FIG. 3 shows a detail of a cross-section of a cylinder crankcaseaccording to a first exemplary embodiment of a first cylinder crankcasetype according to the present invention,

FIG. 4 shows a longitudinal section from FIG. 3 corresponding to Y-Y,

FIG. 5 shows a detail of a cross-section of a cylinder crankcaseaccording to a second exemplary embodiment of the first cylindercrankcase type according to the present invention,

FIG. 6 shows a longitudinal section from FIG. 5 corresponding to X-X,

FIG. 7 shows a single connection tube as a guide duct to be embedded fora cylinder crankcase,

FIG. 8 shows a tube system to be embedded for a cylinder crankcase,

FIG. 9 shows a detail of a cross-section of a cylinder crankcaseaccording to a third exemplary embodiment of the first cylindercrankcase type according to the present invention,

FIG. 10 shows a second cylinder crankcase type according to the presentinvention in a schematic view from below,

FIG. 11 shows a detail of a cross-section of a third cylinder crankcasetype according to the present invention,

FIG. 12 a shows a detail of a cross-section of a fourth cylindercrankcase type according to the present invention,

FIG. 12 b shows a detail of a longitudinal section corresponding to A-Afrom FIG. 12 a, and

FIG. 13 shows a detail of a cross-section of a further cylindercrankcase according to the present invention.

In the detail of a cast part shown in FIG. 1, a cylinder crankcase 1here, according to the related art, a crankshaft bearing 2 and acamshaft bearing 3, as well as a main oil duct 4 (a main guide duct) areillustrated in cross-section. Furthermore, guide ducts 5 a, 5 b areshown in longitudinal section, which run from the main oil duct 4 to thecrankshaft bearing 2 and/or camshaft bearing 3 and ensure thelubrication of camshaft and crankshaft bearings during engine operation.The guide duct 5 c originating from the camshaft bearing 3 leads to anattachment of the cylinder crankcase 1, in this case to a cylinder head(not shown). The guide ducts 5 a, 5 b, 5 c shown are introducedsubsequently into the cast cylinder crankcase 1, i.e., drilled.Therefore, only a linear course of the guide ducts 5 is possible, andthe housing 1 has accesses 6 to the outside (shown on the left), whichare required by the manufacturing technique and must be closed later.

In FIG. 2, the main oil duct 4 from FIG. 1 is shown in longitudinalsection, and multiple guide ducts 5 b branching therefrom, which lead tobearings 3 for the camshaft, may be seen. Furthermore, openings 22 inthe contour region of the cylinder crankcase 1 are shown. Correspondingopenings 22 may also be seen in FIGS. 4 and 6.

FIG. 3 shows a cast part according to the present invention for aninternal combustion engine, which has at least one guide duct 5 thatleads a fluid medium to a required location. This part is a cylindercrankcase 1. In this case, the section position corresponds to that fromFIG. 1.

A guide duct 5 d is shown, which is implemented in the form of a tubeand has also been embedded during casting of the cylinder crankcase 1.The single connection tube 7 embedded as the guide duct 5 d isimplemented here as bent, “like a suitcase handle”. Of course, a guideduct 5 d may also have another shape and/or another course than thatshown. From a bend 8, in this case a section 7 a runs to a crankshaftbearing 2, and another section 7 b runs to a camshaft bearing 3. Thebend 8 is located at the point at which the main oil duct 4 will run,which is introduced subsequently through drilling in a typical way inthis exemplary embodiment. When the main oil duct 4 is introducedthrough drilling, the embedded connection tube 7 is drilled through andthe connection of the guide duct 5 d to the main oil duct 4 is thusproduced. In engine operation, oil reaches the particular crankshaftbearing 2 and/or camshaft bearing 3 from the main oil duct 4 via thesections 7 a, 7 b of the guide duct 5 d and/or connection tube 7. Theends of the guide duct 5 d extending into the camshaft bearing 3 and thecrankshaft bearing 2 are required by casting technology and are removedin the course of the finishing. The guide duct 5 c to the cylinder headis introduced through drilling in this exemplary embodiment.

It may be seen in longitudinal section in FIG. 4 that in the firstexemplary embodiment shown, multiple individual connection tubes 7 areembedded as guide ducts 5 for the medium guiding, specifically in theseparation wall 23. One end of each of the “suitcase-handle-like”connection tubes 7 shown here discharges into a camshaft bearing 3 and(interrupted by the drilled-in main oil duct 4) the other end dischargesinto a crankshaft bearing 2.

Of course, it is also possible to embed two separate tubes instead of acurved connection tube, for example, of which one discharges into acrankshaft bearing and the other into a camshaft bearing. Furthermore,it is also possible to supply only one or multiple camshaft bearingswith oil via one tube guide duct or multiple tube guide ducts and supplythe crankshaft bearings in a typical way through mechanically introducedducts. Correspondingly, one or more crankshaft bearings may be suppliedwith oil via one tube guide duct or multiple tube guide ducts and thecamshaft bearings may be supplied in a typical way through mechanicallyintroduced ducts.

In the second exemplary embodiment shown in FIGS. 5 and 6, the main oilduct 4 and the guide ducts 5 to the camshaft bearings 3 and crankshaftbearings 2 are implemented as embedded tubes, and this is implementedthrough a branched, embedded tube system 9. For this purpose, tubeshaving appropriate dimensions (length, diameter, cross-sectional shape,etc.) are connected before the casting into a tube system 9, which hassubsequently been embedded in a suitable casting method.

It is not shown in FIGS. 3 through 6 that the guide ducts 5 embeddedaccording to the present invention as tubes do not have to be completelyenclosed by cast material, i.e., run in the part wall, but rather mayalso run exposed in some sections. Furthermore, the guide ducts 5 mayalso have a bent course tailored to the contour course.

FIG. 7 shows a connection tube 7 for a “suitcase-handle-like” guide duct5 d in different views. The core supports 10 shown are used for lateralsupport during the casting process. However, it is also possible tomanage without core supports 10 if, for example, the ends of theconnection tube 7 have been anchored sufficiently strongly in castingcores.

FIG. 8 shows an example of a tube system 9 according to the presentinvention. Multiple secondary guide ducts 9 b, which lead to theindividual required locations and supply them with the appropriatemedium, branch off from a main guide duct 9 a.

In the third exemplary embodiment of a cylinder crankcase 1 illustratedin FIG. 9, multiple individual “suitcase-handle-like” connection tubes 7are—corresponding to the first exemplary embodiment from FIGS. 3 and4—embedded as guide ducts 5 d during casting of the crankcase. In thiscase, the crankshaft bearing 2 and the camshaft bearing 3 are suppliedwith a lubricant from the main oil duct 4, which is introducedsubsequently through drilling and intersects each of the connectiontubes 7, via the sections 7 a, 7 b. In contrast to the first exemplaryembodiment, here the guide ducts 5 c to the cylinder heads are notdrilled subsequently into the cylinder crankcase 1, but rather are alsoimplemented in the form of tubes embedded during casting of thecrankcase, through which an additional finishing step on the cast partis advantageously saved. A connection tube 7 and a tube for implementingthe guide duct 5 c are each connected to one another for this purposebefore the casting.

Of course, a guide duct 5 c to the cylinder head may also branch offfrom a connection tube 7 at a different location than that shown. It isalso possible for a guide duct 5 c not to be supplied with lubricant viaa connection tube 7, but rather directly from the drilled main oil duct4 (e.g., by embedding separate, appropriately positioned tubes toimplement guide ducts 5 c for supplying the cylinder heads).Furthermore, the guide ducts 5 c, which lead to the cylinder heads andare implemented as embedded tubes, may also be part of an embedded tubesystem (corresponding to the second exemplary embodiment shown in FIGS.5 and 6) and branch off either directly from the tubular main oil duct 4or from secondary guide ducts 9 b. In addition, a tubular guide duct 5 cmay not branch off from the main oil duct 4, a connection tube 7, asecondary guide duct 9 b, etc., but rather discharge in the region of abearing (here, for example, the camshaft bearing 3, but other bearingsare also possible) into a groove of a bearing ring and be supplied withlubricant from there.

FIG. 10 shows a further cylinder crankcase 1 according to the presentinvention as a cast part for an internal combustion engine. Oil panconnection surfaces 14, to which an oil pan is attachable, may be seenlaterally. The cylinder crankcase 1 has at least one guide duct 5 e,which leads a fluid medium to a required location, is implemented in theform of a tube, and is embedded during casting of the cylinder crankcase1. In the cylinder crankcase 1 according to the present invention shownhere, the guide duct 5 e embedded as a tube forms an oil supply line 11for piston cooling, i.e., conducts oil as the fluid medium to a requiredlocation. The oil supply line 11 ends here above a depression 21 on aface 15 of the cylinder crankcase 1 and is supplied with oil from an oilpump. Of course, lubricant may also be fed into the oil supply line 11at another location of the oil loop within the cylinder crankcase 1.

In the exemplary embodiment shown, multiple cylinders 12 areadvantageously supplied from a shared oil supply line 11. For thispurpose, the embedded tube guide duct 5 e is positioned in thelongitudinal extension of the cylinder crankcase 1, i.e., transverselyto the cylinders 12. It runs here in the region of the crank chambers onthe lower cylinder regions at a certain distance to the cylinderexternal walls. It may be seen that the guide duct 5 e is tailored tothe form of the cylinder 12, so that a “wavy” curved shape results. Theoil supply line 11 is implemented as essentially exposed in theexemplary embodiment. It is locally enclosed with cast material of thepart, like a “shell”, at multiple locations. These cast supports 13produce a solid bond of oil supply line 11 and part. The cast supports13 also form the mounting points for the spray nozzles (not shown). Thespray nozzles are subsequently mechanically introduced into the oilsupply line 11 and are each implemented and positioned in such a waythat they spray lubricant directed into a cylinder chamber below apiston floor. The pistons are thus cooled and, in addition, the cylinderwalls are lubricated.

Through the curved, tailored course of the oil supply line 11 for thepiston cooling and through its predominantly exposed implementation,which is only locally enclosed by cast material, a significant reductionin weight of the part and savings in mechanical machining effort isachieved in relation to the known oil supply lines, which are drilledlinearly into cast material.

Of course, the oil supply line 11 may also have another course and/oranother position or even be completely enclosed over the entire lengthor larger regions. Furthermore, multiple guide ducts 5 e, which form oilsupply lines 11 for piston cooling, may also be embedded. If necessary,the oil supply line 11 may also advantageously have differentcross-sectional shapes in its course.

FIG. 11 shows another cylinder crankcase 1 according to the presentinvention as a cast part for an internal combustion engine, which has atleast one guide duct 5 f, which leads a fluid medium to a requiredlocation, is implemented in the form of a tube, and is embedded duringcasting of the cylinder crankcase 1. In the cylinder crankcase 1according to the present invention shown here, the guide duct 5 f, whichis embedded as a tube, forms a pressurized oil line 16 to a cylinderhead.

The pressurized oil line 16, embedded as a tube, is directly suppliedwith lubricant from a main oil duct 4 here. In the exemplary embodimentshown, the connection of the guide duct 5 f to the oil loop is producedthrough the subsequent drilling of the main oil duct 4. Alternatively,the pressurized oil line 16 may also be fed from another region of theoil economy within the cylinder crankcase 1, in that it has beenconnected to another oil-guiding line to form a tube composite beforebeing embedded in the cylinder crankcase, for example, (cf. FIG. 9) orin that it discharges into a groove of a bearing. Numerous furtheradvantageous variations are possible.

Because of an obstruction 17—in the exemplary embodiment shown, athreaded hole 18 and another opening 19 are illustrated as examples—theguide duct 5 f embedded as a tube has a course tailored to the contourcourse and is bent “like a curve” here. Obviously, other course shapesare also possible as a function of constructive conditions. Thepressurized oil line 16 is completely enclosed by cast material inlongitudinal extension here. Alternatively, depending on theconstructive conditions, it may also be advantageously positioned insuch a way that it runs partially or completely exposed in somesections. Furthermore, it may advantageously have differentcross-sectional shapes in its course in order to overcome narrow pointsin the cylinder crankcase 1, for example.

The pressurized oil line 16 to the cylinder head, which is embedded inthe cylinder crankcase 1, ends at a cylinder head connection surface 20.The expedient number of pressurized oil lines 16 embedded as tubes forsupplying oil to the cylinder head and/or the cylinder heads via thecylinder crankcase 1 is a function of the particular equipment of theengine.

The implementation of the cylinder head oil supply in the form of anembedded tube and/or multiple embedded tubes is very advantageous forthe designer, since he does not have to introduce his oil ductlinearly—as in the case of mechanical introduction by drilling—butrather may introduce it curved and therefore tailored to the spatialconditions.

FIGS. 12 a and 12 b show yet another cylinder crankcase 1 according tothe present invention as a cast part for an internal combustion engine,which has at least one guide duct 5 g, which leads a fluid medium to arequired location, is implemented in the form of a tube, and is embeddedduring casting of the cylinder crankcase 1. In the cylinder crankcase 1according to the present invention shown here, the guide duct 5 gembedded as a tube forms a fuel line 24 for supplying a fuel pump withfuel as the fluid medium. The curved line 25 in FIG. 12 a indicates thatthe illustration of the embedded fuel line 24 lies in a differentsectional plane than the rest of the drawing.

It may be seen that multiple guide ducts 5 g are advantageously eachembedded as a tube in an external wall 26 of the cylinder crankcase 1,and they run in the longitudinal extension of the cylinder crankcase 1(cf. FIG. 12 b). In this case, the central fuel line 24 in the exampleshown is a fuel supply line and the external fuel lines 24 are each fuelreturn lines. Of course, other numbers of embedded lines and/or otheroccupations of the lines are possible. Furthermore, an opening 27 isshown in FIG. 12 a, into which a fuel pump is later inserted. As may beseen in the detail of a longitudinal section in FIG. 12 b, multipleopenings 27 for fuel pumps are provided over the length of the centralfuel line 24, the number being a function of the cylinder count of theparticular engine.

In the course of finishing measures on the cast part, the fuel supplyline is cut and/or cut through in the regions of each of the openings 27for the fuel pumps and the connections between guide duct 5 g and pumpsare thus produced. Openings in the fuel return lines are also laterintroduced mechanically. Fuel is taken from the supply line by each fuelpump and pumped to a spray nozzle in the cylinder head through aconnection line.

According to the related art, fuel lines are mechanically introducedinto the external wall of a cylinder crankcase as long, linear holes.Embedding one or more fuel line(s) as tubes using the manufacturingmethod according to the present invention offers the advantageouspossibility that the guide duct may be curved if necessary. It mayadvantageously run exposed, predominantly or in sections, may even havenon-round cross-sectional shapes, or may have different cross-sectionalshapes in its course. Thus, for example, a reduction of the part wallthicknesses is possible, which results in savings in material and weightas well as reduced manufacturing costs. Furthermore, the course of thelines may be optimized. Since the fuel line(s) 24 is/are alreadyprovided integrated in the finished cast part, the work effort isadditionally significantly reduced overall.

It may be seen in the exemplary embodiment of a cylinder crankcase 1according to the present invention shown in FIGS. 12 a and 12 b thathere only the fuel lines 24 are embedded as tubes in the crankcase. Theguide ducts 5 a, 5 b, which run in a separation wall 23, for supplyingcamshaft bearing 3 and crankshaft bearing 2 with oil, as well as asupply duct 5 c to the cylinder head, are subsequently introducedmechanically through drilling here.

The embodiments according to the present invention described above inthe form of four cylinder crankcase types according to the presentinvention—specifically a) oil supply of crankshaft bearing and/orcamshaft bearings by at least one guide duct embedded as a tube (cf.FIGS. 3 to 8), b) oil supply for piston cooling by at least one guideduct embedded as a tube (cf. FIG. 10), c) oil supply of the cylinderhead and/or the cylinder heads by at least one guide duct embedded as atube (cf. FIGS. 9, 11), and d) providing a fuel line through at leastone guide duct embedded as a tube (cf. FIG. 12)—may advantageously alsobe implemented in an expedient combination on the same cylindercrankcase.

An example of an advantageous combination of this type is shown in FIG.13. A cylinder crankcase 1 is shown therein, in which the supply ofcrankshaft bearings 2 and camshaft bearings 3 with lubricant isimplemented by bent guide ducts 5 d embedded in the separation wall 23(corresponding to the exemplary embodiment described in FIGS. 3 and 4).In addition, a guide duct 5 c embedded as a tube is provided here, whichforms a pressurized oil line 16 to a cylinder head. Contrary to theexemplary embodiment shown in FIG. 11, this line is not supplied withoil directly from the main oil duct 4, but rather branches off from theembedded guide duct 5 d. In addition, guide ducts 5 g embedded as tubesare provided, which form fuel lines 24 (supply line and return lines)for supplying a fuel pump (corresponding to the exemplary embodiment ofFIG. 12).

Numerous further combinations may advantageously be implemented and arealso included by the present invention, e.g., an embedded bearing supplyvia separate connection tubes 7 or an embedded tube system 9 inconnection with an embedded supply line 11 for piston cooling; anembedded supply line 11 for piston cooling in connection with anembedded fuel line 24; an embedded pressurized oil line 16 to thecylinder head in connection with an embedded fuel line 24, etc.

The guide ducts 5 illustrated in the exemplary embodiments as examplesfor oil supply and fuel supply may correspondingly also be transferredto guide ducts 5 for another medium.

The present invention was described in this case for a cylindercrankcase 1, the cylinder crankcase able to be implemented in one pieceor in multiple pieces and/or the crankcase also able to have a cylindercase placed thereon. Of course, the present invention is not restrictedto the cylinder crankcase 1, but rather may also be transferred to oneor more attachment(s) for the cylinder crankcase 1—particularly tocylinder heads, gear case, chain case, oil pans—and to other partsmanufactured in a casting process.

LIST OF REFERENCE NUMBERS

-   1 cylinder crankcase-   2 crankshaft bearing-   3 camshaft bearing-   4 main oil duct-   5 guide duct (general)-   5 a guide duct-   5 b guide duct-   5 c guide duct-   5 d guide duct-   5 e guide duct-   5 f guide duct-   5 g guide duct-   6 access-   7 connection tube-   7 a section of 7-   7 b section of 7-   8 bend-   9 tube system-   9 a main guide duct-   9 b secondary guide duct-   10 core support-   11 oil supply line for piston cooling-   12 cylinder-   13 cast support-   14 oil pan connection surface-   15 face of 1-   16 pressurized oil line-   17 obstruction-   18 threaded hole-   19 opening-   20 cylinder head connection surface-   21 depression-   22 opening-   23 separation wall-   24 fuel line-   25 bent line-   26 external wall-   27 opening for fuel pump

1. A cast part for an internal combustion engine, the part being acylinder crankcase (1), which has at least one guide duct (5, 5 d),which leads a fluid medium to a required location, the duct beingimplemented in the form of a tube and being embedded inside the partwhen the latter is cast, the fluid medium being oil and the at least oneguide duct (5, 5 d) being an oil supply line to a crankshaft bearing (2)and/or camshaft bearing (3) to be lubricated as the required location,wherein the cylinder crankcase (1) comprises multiple embedded guideducts (5, 5 d) which are each introduced as an individual connectiontube (7) for guiding the medium, the connection tubes (7) being eachbent and each having a bend (8) from which one section (7 a) runs to acrankshaft bearing (2) and another section (7 b) runs to a camshaftbearing (3), the bends (8) of the embedded connection tubes (7) eachbeing located at positions at which a main oil duct (4) subsequentlyintroduced through drilling runs, so that by introducing the main oilduct (4), the connection tubes (7) are drilled through and a connectionof a connection tube (7) to the main oil duct (4) is thus produced ineach case.
 2. The cast part according to claim 1, wherein the connectiontubes (7) are implemented as tailored to the contour course,advantageously bent “like a suitcase handle”.
 3. The cast part accordingto claim 1, wherein the cylinder crankcase (1) comprises at least oneguide duct (5 c) for oil, embedded as a tube, which leads to a cylinderhead.
 4. The cast part according to claim 3, wherein the at least oneguide duct (5 c) to the cylinder head branches off from an individualconnection tube (7).
 5. The cast part according to claim 3, wherein theat least one guide duct (5 c) to the cylinder head is a separatelyembedded tube which is supplied with oil directly from a drilled mainoil duct.
 6. The cast part according to claim 1, wherein the cylindercrankcase (1) comprises at least one guide duct (5 e) embedded as atube, which forms a supply line (11) for piston cooling.
 7. The castpart according to claim 1, wherein the cylinder crankcase (1) comprisesat least one guide duct (5 g) embedded as a tube, which forms a fuelline (24) for supplying a fuel pump.
 8. A cast part for an internalcombustion engine, the part being a cylinder crankcase (1) which has atleast one guide duct (5, 5 e), which leads a fluid medium to a requiredlocation, the duct being implemented in the form of a tube and beingembedded inside the part when the latter is cast, wherein the fluidmedium is oil and the at least one guide duct (5 e) embedded as a tubeforms a supply line (11) for piston cooling; wherein the supply line(11) for piston cooling is implemented as essentially exposed and islocally enclosed with cast material of the part, like a “shell”, atmultiple locations so that cast supports (13) are formed; and whereinthe cast supports (13) are mounting points for spray nozzles, which canbe subsequently mechanically introduced into the supply line (11) forpiston cooling and which are each implemented and positioned in such away that they spray lubricant directed into a cylinder chamber below apiston floor.
 9. The cast part according to claim 8, wherein the supplyline (11) for piston cooling is positioned in the longitudinal extensionof the cylinder crankcase (1) and multiple cylinders (12) are suppliedwith oil from a shared supply line (11).
 10. The cast part according toclaim 8, wherein the cylinder crankcase (1) comprises at least one guideduct (5 f) embedded as a tube, which forms a pressurized oil line (16)to a cylinder head.
 11. The cast part according to claim 8, wherein thecylinder crankcase (1) comprises at least one guide duct (5 g) embeddedas a tube, which forms a fuel line (24) for supplying a fuel pump.
 12. Acast part for an internal combustion engine, the part being a cylindercrankcase (1), which has at least one guide duct (5, 5 f), which leads afluid medium to a required location, the duct being implemented in theform of a tube and being embedded inside the part when the latter iscast, wherein the fluid medium is oil and the at least one guide duct (5f) embedded as a tube forms a pressurized oil line (16) to a cylinderhead; and wherein one end of the pressurized oil line (16) is positionedat a position at which the main oil duct (4) subsequently introducedthrough drilling runs and the other end of the pressurized oil line (16)ends at a cylinder head connection surface (20).
 13. The cast partaccording to claim 12, wherein the pressurized oil line (16) has a bentcourse tailored to the contour course of the cylinder crankcase (1). 14.The cast part according to claim 12, wherein the cylinder crankcase (1)comprises at least one guide duct (5 g) embedded as a tube, which formsa fuel line (24) for supplying a fuel pump.
 15. A cast part for aninternal combustion engine, the part being a cylinder crankcase (1),which has at least one guide duct (5, 5 g), which leads a fluid mediumto a required location, the duct being implemented in the form of a tubeand being embedded inside the part when the latter is cast, wherein thefluid medium is fuel and the at least one guide duct (5 g) embedded as atube forms a fuel line (24) for supplying a fuel pump; wherein the fuelline (24) is positioned in the longitudinal extension of the cylindercrankcase (1); and wherein the fuel line (24) is a fuel supply line andwherein multiple openings (27) for fuel pumps are provided in thecylinder crankcase (1) over the length of the fuel supply line, the fuelsupply line being cut and/or cut through in the regions of each of theopenings (27) for fuel pumps in the course of finishing measures on thecast part and the connections between guide duct (5 g) and fuel pumpssubsequently inserted into the openings (27) for fuel pumps being thusproduced.
 16. The cast part according to claim 14, further comprising afuel return line.
 17. A method for manufacturing a cast part for aninternal combustion engine, the part being a cylinder crankcase (1),which has at least one guide duct (5), which leads a fluid medium to arequired location, wherein, to form the at least one guide duct (5), atube having the desired course is installed in a casting mold requiredfor casting or is introduced into a casting core or is incorporated intoa lost model and/or into its form medium cavity filler and subsequentlythe part is cast using the particular casting method to be employed,wherein multiple guide ducts (5, 5 d) are embedded inside the cylindercrankcase (1) in the form of individual connection tubes (7) andsubsequently a main oil duct (4) is mechanically introduced into thecylinder crankcase (1) through drilling, so that the connection tubes(7) are drilled through and a connection of a connection tube (7) to themain oil duct (4) is thus produced in each case.
 18. The methodaccording to claim 17, wherein the part is cast in a casting methodusing a lost mold.
 19. The method according to claim 17, wherein thepart is cast in a casting method using a permanent mold.
 20. The methodaccording to claim 17, wherein the part is cast in the lost foam method.